The reaction H₂(g) + I₂(g) → 2 HI(g) has a measured standard enthalpy change of +26…

CHEMISTRY · Single correct · A Level · Chemistry · Energetics · Energetics

Problem

The reaction H₂(g) + I₂(g) → 2 HI(g) has a measured standard enthalpy change of +26 kJ mol⁻¹ at 298 K. Using the average bond energies H–H 436 kJ mol⁻¹ and I–I 151 kJ mol⁻¹, which of the following is the best estimate for the average H–I bond energy in kJ mol⁻¹? (a) 4.36×102  kJ mol−14.36\times 10^{2}\;\text{kJ mol}^{-1} (b) 2.0×102  kJ mol−12.0\times 10^{2}\;\text{kJ mol}^{-1} (c) 2.8×102  kJ mol−12.8\times 10^{2}\;\text{kJ mol}^{-1} (d) 3.06×102  kJ mol−13.06\times 10^{2}\;\text{kJ mol}^{-1}

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